<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      .box {
        width: 300px;
        height: 300px;
        border: 1px solid red;
        position: relative;
        margin: 100px auto;
        transform: rotate(45deg);
        background-color: red;
      }
      .box::before {
        content: "";
        position: absolute;
        width: 300px;
        height: 300px;
        border-radius: 50%;
        border: 1px solid red;
        background-color: red;
        left: -150px;
      }
      .box::after {
        content: "";
        position: absolute;
        width: 300px;
        height: 300px;
        border-radius: 50%;
        background-color: red;
        border: 1px solid red;
        top: -150px;
      }

      .box1 {
        width: 50px;
        height: 50px;
        border-top: 100px solid red;
        border-right: 100px solid blue;
        border-bottom: 100px solid green;
        border-left: 100px solid yellow;
      }

      .box3 {
        width: 100px;
        height: 100px;
        border: 0px solid transparent;
        border-top: 40px solid #f00;
        border-radius: 100px 0 0 0;
      }
      .box4 {
        width: 100px;
        height: 100px;
        border: 0px solid transparent;
        border-top: 40px solid #f00;
        border-radius: 0 100px 0 0;
      }
      .box2-1 {
        width: 50px;
        height: 50px;
        border: 1px solid #f00;
        border-radius: 0 50% 0 50%;
      }
    </style>
  </head>
  <body>
    <div class="box"></div>

    <div class="box1"></div>

    <div class="box2-1"></div>

    <div class="box3"></div>
    <div class="box4"></div>
  </body>
</html>
